1. Field of the Invention
The present invention concerns, in general, electrical machines, such as a permanent magnet motor, as well as a method for forming the windings contained therein.
2. Brief Description of the Related Art
Electrical machines are generally known and are used for various purposes and applications; they can, for example, be designed as ‘brush’ motors or ‘brushless’ motors, such as commonly used in motor vehicle applications, for example. For example, these types of motors include motors to adjust seats as well as drive motors used to rotate pumps or fan elements. Such electrical machines contain a stator and a rotor having magnetic poles. In this case, the stator is provided with windings, usually made of copper wire, which when wired accordingly generate a fluctuating electromagnetic field for the purpose of driving the rotor. The electrical machine can also be a generator.
The continually increasing requirements in relation to minimal weight and for attaining a small internal volume, while retaining or even increasing the power density and capacity, remain an ongoing challenge in efforts to improve such electrical machines. To design the manufacturing process as efficiently as possible, various winding methods have been devised; one skilled in the art would be familiar with, in particular, the so-called linear winding technique, the so-called flyer winding technique, the so-called needle winding technique, and the so-called ring core winding technique. When manufacturing large numbers of electrical machines, such as for automotive applications, usually either the needle winding technique or the flyer winding technique is used. A double winding on the rotor has been attempted in relation to both the so-called needle winding technique and flyer winding technique in order to reduce the length of the winding overhang. For this special application, wire with an accordingly reduced diameter was wound twice according to the traditional winding scheme, which considerably extended the manufacturing process while also rendering aspects relating to connection more complicated due to the increased number of connection wires requiring connection to their respective commutator hooks.
An example of a winding procedure is disclosed in WO 2012101961. Furthermore, another procedure as well as a corresponding electrical machine are known from DE 102011003049. This document details attempts to achieve the greatest possible degree of filling and therefore also to make the needle space itself useful, which is achieved by winding the wire in a figure eight shape.
Accordingly, the problem of the present invention is to provide an electrical machine in which at least one element is optimized among the requirements for internal volume, capacity or weight, while simultaneously keeping the other parameters the same.
Another task of the invention is to provide methods capable of providing the windings for such an improved electrical machine.